How local anesthesia is done. Types of local anesthesia

Choosing a pain relief method

An anesthesiologist is responsible for the anesthesia process. He, together with the surgeon and the patient, decides what type of anesthesia will be used for each patient individually.

The choice of anesthesia method for a particular surgical procedure is influenced by many factors. Firstly, of course, the anesthesiologist takes into account the scope of the intervention planned by the surgeon. It is clear that now no one performs appendicitis removal under local anesthesia, but the removal of a mole, for example, does not require deep medicated sleep.

Secondly, the choice of anesthesia method is influenced by the patient’s condition. If the patient is in serious condition and any complications of surgery or anesthesia are expected,

Thirdly, the anesthesiologist takes into account the experience and qualifications of the surgeon in order to know approximately what direction the operation will take. In addition, the anesthesiologist, if given the opportunity to choose one or another method of pain relief, will always choose the one that he himself is better at.

If the situation allows, the patient can choose the method of anesthesia. For example, when caesarean section A woman may choose to have spinal anesthesia in order to be conscious when her baby is born, while other women prefer to go to sleep to better cope with this period of excitement.

What you need to know if you are undergoing local anesthesia or anesthesia

It is very important for the patient to establish contact with the anesthesiologist. Carrying out his instructions for the patient and correct patient behavior greatly facilitates the process of pain relief and improves the prospects for treatment.

Before the operation, the doctor will ask you about previous surgical interventions, so try in advance, if possible, to tell in chronological order what operations were performed and for what reason. What type of anesthesia was used and how did you tolerate it?

Before surgery, remember the diseases you have had throughout your life. Don't forget to mention any chronic diseases you have at the time of surgery.

If you are taking any medications, tell your doctor their name and, if possible, their dosage.

The doctor will ask you about the blood pressure numbers that are usually typical for you.

In addition to all of the above, the anesthesiologist may ask additional questions and order additional tests in order to finally decide on the choice of pain relief method.

Local anesthesia

What is it: Local anesthesia usually does not require the presence of an anesthesiologist. Surgeons are fluent in this anesthesia technique. The area of ​​the body where the intervention will be performed is anesthetized layer by layer with a solution of local anesthetic.

When used: usually for minor operations, for example, removal of a mole, papilloma, surgery for a non-strangulated hernia, elimination of phimosis or testicular hydrocele

What the patient needs to know: when local anesthesia There is always a risk of insufficient pain relief, but often patients, especially impressionable individuals, already in anticipation of pain, say that they feel everything that the surgeon does, although in fact, if you distract the patient and pinch the skin where the operation will be performed, he will even won't feel it.

If you feel any discomfort or pain, do not panic. Ask your doctor to stop for a while and add pain relief. A tactful approach to a health care worker is a guarantee of courteous treatment of the patient.

Spinal anesthesia

What is it: during spinal anesthesia, a local anesthetic solution is injected directly into the space between the membranes spinal cord. This is done under local anesthesia of the skin and underlying tissues in the lumbar region, so that the patient spinal anesthesia feels only one prick, like dental pain relief. After intraspinal administration of the anesthetic, the lower torso and lower extremities lose pain sensitivity.

When used: spinal anesthesia is successfully used during operations for varicose veins of the legs, during surgical interventions in urology, gynecology, and traumatology. The attitude of anesthesiologists and obstetricians-gynecologists towards pain relief during labor using spinal anesthesia is ambiguous.

What the patient needs to know: After a standard interview, the anesthesiologist asks the patient to lie on his side with his legs adducted to his stomach or, more often, to sit on the operating table with his back arched, like a cat. It is very important to maintain the given position, as this is necessary for the correct progress of the procedure. Spinal anesthesia with good local anesthesia is almost painless.

Epidural anesthesia

What is it: with an epidural anesthesia in the space between the spinal cord and spinal canal a catheter is inserted - a one-ton tube through which a solution of local anesthetic and even narcotic painkillers can be injected.

When used: In Western countries, epidural anesthesia is used to relieve pain during labor. In our country, this method of labor pain relief has not yet become widespread. Typically, this type of anesthesia is used for long-term gynecological or urological operations.

What the patient needs to know: epidural anesthesia is carried out after a standard interview and examination of the patient, during which the absence or presence of contraindications to this type of anesthesia is determined. After inserting the catheter, the end through which medications will be administered is usually placed on the patient's shoulder for convenience. As needed, the doctor will be able to add necessary medications.

Mask anesthesia

What is it: sleep during anesthesia is maintained using a special gas, which is supplied through a mask applied directly to the patient’s face.

When used: for surgical interventions that take a relatively short time, for example, reduction of a fracture or dislocation, opening of a subcutaneous abscess.

What the patient needs to know: during mask anesthesia, it is important to work harmoniously with the doctor, breathe as he asks, follow the commands he says, and answer the questions asked by the doctor. With adequate contact between the anesthesiologist and the patient, mask anesthesia allows you to quickly put the patient to sleep and also quickly wake him up.

Intravenous anesthesia

What is it: drugs that cause pain relief and induce a state of medicated sleep are injected into a vein. This also allows you to most often achieve a quick effect.

When to use: Intravenous anesthesia can be used for various operations. Often, intravenous anesthesia as the only method of pain relief is used to terminate pregnancy, during hysteroscopy, in so-called “minor” surgery, and during some urological operations.

What the patient needs to know: Since all drugs that provide pain relief will be injected into a vein, it is imperative to discuss with the doctor any allergic reactions to any substances in the past.

Multicomponent general anesthesia with muscle relaxation

What is it: this anesthesia is called multicomponent because with this type of anesthesia, drugs for pain relief and sleep are administered both intravenously and in the form of gases through the airways. This allows you to achieve the most adequate pain relief.

When to use: this type anesthesia is absolutely indicated for patients with severe pathology. In addition, all “major” operations are performed only under multicomponent anesthesia. Currently, under this type of anesthesia, they operate on the organs of the abdominal cavity, chest, and carry out long-term operations on the organs of the retroperitoneal space. If the patient does not want to be conscious during the operation, this anesthesia can be used at his request and in the absence of contraindications.

What the patient needs to know: the survey conducted by the anesthesiologist must be approached very responsibly. Do not hide any information regarding your health from your doctor. It is important to follow the doctor’s commands and respond adequately to them. After such general anesthesia, nausea and slight dizziness are possible. Any concerns should be reported to your doctor. After the operation, the anesthesiologist, together with the surgeon, will necessary appointments. You are prohibited from eating or drinking for two hours after surgery.

Everyone has heard about local anesthesia and general anesthesia, but not everyone knows the meaning of these words. This is a means of protecting the patient from pain during medical procedures, in which pain shock is possible without anesthesia. In medicine, local and general anesthesia is widely used - loss of sensitivity after the use of special drugs. Let us examine in more detail which anesthesia is best to use and what kind of anesthesia is used.

The development of methods of pain relief is carried out by a special branch of medical science - anesthesiology. Doctors in this specialty monitor the patient’s condition during anesthesia. Nowadays, there are many drugs used for temporary loss of sensitivity.

Types of anesthesia and methods of administration

General anesthesia is accompanied by complete loss of consciousness by the patient. Used for long-term heavy operations. Local anesthesia is performed for minor interventions.

The difference between them lies both in the methods of drug administration and in the effect they have on the human body. Methods of drug administration:

It is not necessary to use one drug to achieve analgesia. The type of general anesthesia is determined by the type of operation. Combined anesthesia is often used, when one drug is used to quickly achieve the state of necessary analgesia, and then another drug is used to maintain pain relief.

In addition to the anesthetic agent, other medications are sometimes required. In particular, inhalation endotracheal general anesthesia, which requires relaxation of the respiratory muscles, for which the patient is given medicinal substances from the group of muscle relaxants.

In cases where local anesthesia is used, additional drugs can be dispensed with. The substance used to numb a specific area is injected superficially. The administration does not require special preparation, with the exception of treating the injection site with an antiseptic.

IN Lately Anesthetic solutions are produced in the form of an aerosol, which allows them to be widely used in sports medicine. This form of drug release allows you to quickly numb the site of injury.

How does local anesthesia work?

Some procedures use local anesthesia, or topical anesthesia, to numb a small area during medical procedures.

As a rule, it is used during minor operations and is widely used in dentistry.

The essence of the method is to suppress the sensitivity of peripheral nerve fibers. It could be skin pain receptors, then the skin at the site of the procedure is pricked with an anesthetic solution.

Conduction anesthesia can be considered as a local anesthesia. In this case, the drug is administered along a large nerve bundle responsible for sensitivity in this area. This also includes spinal anesthesia, when the drug is injected into the spinal cord, and the patient loses sensation below the injection site. This is commonly used for caesarean sections and is called .

An undoubted advantage over general anesthesia is the ease of implementation. This allows a doctor of any specialty, not necessarily an anesthesiologist, to provide anesthesia. Usually, for minor interventions, the surgeon himself injects the anesthetic in the area he needs. The patient feels pain only at the moment of the injection itself, which is due to the use of a thin needle.

In modern medicine, operations are increasingly performed under local anesthesia. This is possible thanks to the development of medical technologies, which make it possible to perform even significant operations through a small access.

Contraindications and side effects local anesthesia cannot compare with those for general anesthesia. But, unfortunately, negative consequences are possible. Local anesthetic drugs can have a toxic effect, affecting the nervous and cardiovascular systems.

Sometimes, the expression local anesthesia evokes negative associations in the patient. Doctors have to resort to sedatives to calm the patient.

Stages of pain relief

General anesthesia makes it possible to put the patient into a state of complete loss of all types of sensitivity. Its use allowed us to open a new chapter in surgery. General anesthesia is a means of protecting the patient from the consequences of trauma, which is any surgical procedure.

How is general anesthesia done?

Depression of the central nervous system leads to the patient losing consciousness. When general anesthesia is used for surgery, the participation of an anesthesiologist is required. It is necessary to maintain a certain stage of anesthesia in order to be able to bring the patient out of this state. There is a concept of depth of anesthesia. This concept reflects the stage in which the patient is currently located. The following stages are distinguished:

• I - stage of analgesia;
• II - stage of excitation;
• III - stage of surgical anesthesia:
• IV - agonal stage.

General anesthesia of the third stage, in turn, is divided into the following levels:

• Level 1 (III) - superficial anesthesia;
• Level 2 (III) – easy;
• 3rd level (III) - deep;
• Level 4 (III) - super deep.

The anesthesiologist’s task is to bring the patient to stage III, but to prevent it from progressing to stage IV.

The drugs that can be used for anesthesia differ in the severity of these stages. During the Great Patriotic War, during minor operations, intravenous administration of ethyl alcohol was used, which is characterized by a long excitation stage and a short surgical stage.

Currently, combinations of drugs are used, which allows you to quickly bring the patient to the stage of surgical anesthesia and maintain it long time. An example of induction anesthesia is intravenous administration of sodium hydroxybutyrate, followed by intubation and inhalation anesthesia, since the concentration of gaseous substances is easier to control. The noble gases helium and xenon have found application in anesthesiology.

While the patient is in a state of sleep, clear control over his vital signs is necessary: ​​pulse, blood pressure, oxygenation.

The disadvantages of general anesthesia include its severity for the body and excessive oppressive force. After surgery, the patient must be transferred to the department intensive care, where he is under constant observation throughout the day.

Side effects and contraindications

There is no doubt that anesthesia is harmful to the body. Impact potent drugs on the human nervous system can cause serious complications.

This is due to, namely, pathology internal organs in a state of decompensation, heart rhythm disturbances, headaches, endocrine system disorders, childhood, alcohol and drug intoxication and many others.

Contraindications are not always absolute. Perform general anesthesia in childhood acceptable in case of emergency requiring immediate surgical intervention. The inadmissibility of pain relief in alcohol and drug intoxication is due to the patient’s resistance to anesthesia, which leads to the need to increase the dose of the drug.

Suppression of the nervous system can cause damage in many organs. This is due to a violation of their innervation and functioning. Side effects associated with the respiratory system include the patient’s loss of ability to breathe independently, a reaction to a drug leading to spasm airways, changes in blood gas composition.

The cardiovascular system may respond to anesthesia by increasing or decreasing blood pressure. Various types of arrhythmias are possible, and myocardial infarction can be provoked. Putting a patient under anesthesia causes an imbalance in the homeostasis system, which can lead to hormonal imbalances and disturbances in the thermoregulation system.

The consequences of general anesthesia in childhood may be more severe, but there is no clear evidence of the effect of anesthetics in early childhood on the development of the nervous system. Therefore, in all cases of surgical care for children, local anesthesia is recommended.

Much credit for the development of local anesthesia belongs to Russian scientists: V.K. Anrep, who discovered the local anesthetic properties of cocaine in 1880, A.I. Lukashevich, who began performing operations under conduction anesthesia in 1886, and especially A.V. Vishnevsky ( 1874—1948). He was a wonderful surgeon who did a lot for the development of general and military surgery. He developed the most safe method local anesthesia, thanks to which hundreds of thousands of wounded during the war were provided with the full necessary surgical care.

MECHANISM OF LOCAL ANESTHESIA

The main differences between local anesthesia and general anesthesia are the preservation of consciousness and the creation of an obstacle to the path of pain impulses below the brain or, more precisely, not above thoracic spinal cord. On this path, you can achieve both pain relief and eliminate other sensations - heat and cold, touch and pressure.

Anesthesia can be performed in the following areas: 1) the surface of the laryngeal mucosa. trachea, bronchi, urethra And Bladder(this is superficial, or terminal, anesthesia); 2) turning off pain receptors in the skin and other organs (infiltration and regional anesthesia); 3) along the course of a large nerve or nerve plexus (conductor anesthesia); 4) along the nerve roots outside the dura mater meninges(epidural anesthesia); 5) at the level of nerve cells that conduct sensitivity in the spinal cord itself (spinal or spinal anesthesia).

PREPARATIONS FOR LOCAL ANESTHESIA

We will focus on several of the most commonly used substances.

Novocaine(procaine). White powder with a bitter taste, highly soluble in water and alcohol. Novocaine is selectively absorbed nerve tissue and consistently turns off the feeling of cold, heat, pain and, finally, pressure. Active in alkaline tissue reactions. With inflammation (acid reaction in tissues), its activity decreases.

In the form of a 5-10% solution, it is used for anesthesia of mucous membranes, and a 1-2% solution for conduction anesthesia. It is practically not used for epidural and spinal anesthesia due to insufficient effectiveness.

Novocaine is most often used for infiltration anesthesia according to A.V. Vishnevsky.

Dicaine(pantocaine). It is 15 times stronger, but almost as many times more toxic than novocaine. It is used for anesthesia of mucous membranes in the form of 0.25; 0.5; 1 or 2% solutions, less often - for epidural anesthesia: 0.3% solution in fractional doses of 3-5 ml (but not more than 20 ml). The maximum single dose is 0.07 g.

Lidocaine(xylocaine). The drug is 2 times more toxic, but 4 times stronger and acts longer (up to 5 hours) than novocaine. For anesthesia of mucous membranes, 4-10% solutions are used, in ophthalmic practice - 2% solution, for conduction anesthesia - 0.5-2% solution (up to 50 ml), for epidural anesthesia - 2% solution (up to 20 ml), for infiltration anesthesia - 0.5-0.25% solutions (500 and 1000 ml, respectively). Maximum dose 15 mg/kg.

Trimekain(mesocaine). 1.5 times more toxic and 3 times stronger than novocaine. For infiltration anesthesia, use 0.25% and 0.5% solutions of 800 and 400 ml, respectively. For conduction anesthesia - 1% (100 ml) or 2% (no more than 20 ml due to sharp potentiation!) solutions. In the form of a 2.5-3% solution in an amount of 7-10 ml, it is used for epidural anesthesia, and for spinal anesthesia, 2-3 ml of a 5% solution is sufficient. The maximum dose is 10-12 mg/kg.

Bupivacaine(marcaine, anecaine). It is the most powerful and long-acting anesthetic of those discussed above (2-3 times greater than lidocaine). For epidural anesthesia it is usually used as a 0.5% solution. The main dose is 40-50 mg, with a maintenance dose of 15-40 mg. Available in 20 ml bottles (1 ml contains 2.5 or 5 mg of the drug) and 1 ml ampoules (contains 5 mg).

Naropin(ropivacaine). One of the most modern anesthetics. Forms of release of the drug: polypropylene ampoules containing 10 or 20 ml of solution different concentrations(0.2%, 0.75% and 1%), as well as infusion containers of 100 or 200 ml of 0.2% ropivacaine. Duration of action - up to 5 hours. Used for conduction and epidural anesthesia.

Ultracaine D-C Forte . 1 ml of the drug contains 40 mg of articaine hydrochloride and 12 mcg of adrenaline hydrochloride. The drug has low toxicity. Although the drug is intended for use in dental practice, there is currently experience with its use for epidural anesthesia.

PREPARATION OF THE PATIENT

The patient must be examined to exclude contraindications to local anesthesia (excitement, low contact, etc.). When clarifying the medical history, it is necessary to find out whether there have been previous reactions to local anesthesia.

It is necessary to prepare the patient psychologically: the safety and effectiveness of local anesthesia are explained to him.

It is necessary to carry out medication preparation, as with general anesthesia; It is advisable to include sedatives and antihistamines. Dentures are removed and the time of the last meal is checked. They prepare everything necessary to eliminate complications: anticonvulsants, a ventilator, an internal infusion system and vasoconstrictors.

ANESTHESIA OF THE MUCOUS (TERMINAL ANESTHESIA)

This method is often used in ophthalmology, otorhinolaryngology, pulmonology, urology; They are also used during tracheal intubation to prevent reflex reactions. For anesthesia, 4-8 drops are instilled into the conjunctiva and cornea, and 2-8 drops of a 2-5% trimecaine solution are instilled into the nasal mucosa. For anesthesia of mucous membranes bronchial tree 3 ml of 3% dicaine solution is sufficient.

CONDUCTION ANESTHESIA

Brachial plexus block. The patient lies on his back with a pad placed under his neck. The head is turned in the direction opposite to the blockade site. The needle point is 1 cm above the middle of the collarbone. The needle is inserted in the direction of the first rib. When the tip of the needle hits the nerve plexus, there is a feeling of a “shot” in the arm. After this, the needle must be pulled back 0.5 cm to avoid intraneural administration of the drug. For anesthesia, 40-60 ml of a 1% lidocaine solution or 0.25% marcaine solution is administered.

Sciatic nerve block. The patient is placed on the edge of the table. The solution is injected into a point located in the middle of the distance between the greater trochanter tibia and the tip of the coccyx.

Intercostal nerve block. After puncturing the skin, the needle is directed to the lower edge of the overlying rib and immediately, as soon as the tip of the needle touches it, the direction is shifted downward so as not to damage the vein and artery, but to inject the drug into the area of ​​the nerve located below them.

PARAVERTEBRAL ANESTHESIA

This is a type of regional local anesthesia. The essence of the method is a block with a local anesthetic nerve trunks at the point where they emerge from the intervertebral foramina. It is necessary to anesthetize not only the affected segment, for example with intercostal neuralgia, but also two segments above and below it. A local anesthetic solution is injected separately into each segment. 5-10 ml of 0.5% novocaine solution is injected into the point chosen for injection. First, the skin and subcutaneous tissue are anesthetized. Then the needle is directed 4-5 cm lateral and slightly below the intended spinous process until it stops at the transverse process or rib. The needle is slightly removed and again moved forward and downward 1 cm under the rib towards the vertebral body. A local anesthetic is injected here.

With this method, you can get a needle into the pleura or abdominal cavity, injure the spleen or get into the subdural space. Therefore, you should carefully monitor the patient’s reactions and be prepared to deal with complications. But this method can be very useful for eliminating pain after lung surgery and multiple rib fractures.

EPIDURAL ANESTHESIA

The epidural space is located between the dura mater of the spinal cord and the inner surface of the spinal canal. It is filled with loose connective tissue in which the venous plexuses are located; The posterior (sensory) and anterior (motor) roots of the spinal nerves pass through this space. They need to be anesthetized.

The patient is placed on his side, with his legs brought to his stomach (the puncture can also be performed in a sitting position; in this case, a stand is placed under the legs, and the back is bent as much as possible). Depending on the desired level of anesthesia, the injection site is chosen: for anesthesia of the chest - Th 2 - Th3, the upper half of the abdomen - Th7 - Th8, the lower half of the abdomen - Th 10 - Th 11, the pelvis - L 1 - L 2, lower limbs- L 3 - L 4.

The puncture site is treated twice with alcohol (but not iodine!) and covered with sterile linen. A thin needle is used to anesthetize the skin and subcutaneous tissue. Then the epidural anesthesia needle with an attached syringe filled with isotonic sodium chloride solution is inserted strictly along the midline in the intervertebral space. The needle is advanced without violence, only by pressing the 1st finger on the syringe plunger. While the needle passes through the ligaments, despite the pressure, the solution does not flow out of the syringe, but as soon as the end of the needle enters the epidural space, the resistance disappears and the solution begins to leave the syringe. Inject 1-2 ml of isotonic sodium chloride solution, disconnect the syringe from the needle and make sure that it is positioned correctly (no blood or liquid should leak from it). After this, 4 ml of local anesthetic solution (test dose) is administered, carefully observing the patient’s breathing, pulse and consciousness. 5 minutes after administration of the test dose, if there are no signs of spinal anesthesia, the main dose is administered, which is determined by the doctor individually for each patient.

For long-term anesthesia, special needles are used (for example, a Tuohy needle), through which a polyethylene or fluoroplastic catheter is inserted 2-4 cm upward into the epidural space. A solution of local anesthetic is injected through it during the operation as needed.

To prolong the effect of the local anesthetic, 1-2 drops of a 0.01% adrenaline solution are often added per 10 ml of solution. In recent years, to enhance the effect of the local anesthetic, small doses of narcotic analgesics (morphine, promedol, fentanyl) have been added to the solution. This allows you to reduce the dosage of local anesthetic and provide long-term postoperative analgesia.

Anesthesia after the administration of a local anesthetic does not occur immediately, but after a certain period of time, called the hidden or latent period. This interval varies for different local anesthetics, for example, for lidocaine or trimecaine it is 10-15 minutes, and for dicaine or bupivacaine it can reach 20-25 minutes.

Clinical picture epidural blockade develops in the following sequence.

At first, the patient feels a feeling of warmth in the lower extremities, then a feeling of numbness, crawling “pins and needles” appears, and, finally, motor blockade occurs when the patient cannot lift his leg. True, this does not happen in all cases, more often in older people. The degree of development of the blockade is determined by injections with an injection needle. Anesthesia is considered sufficient when the patient ceases to distinguish between sharp and dull touch.

The effect of epidural anesthesia on the body.

central nervous system. Epidural anesthesia does not directly affect the central nervous system. However, the shutdown of a certain part of the body that occurs when it occurs leads to the development of the so-called deafferentation brain, i.e. removing the exciting effect of sensitive impulses coming from the periphery. As a result, brain inhibition occurs, which is manifested by drowsiness and a feeling of calm.

The cardiovascular system. By the time anesthesia sets in, a decrease in blood pressure usually occurs. This is a natural manifestation of epidural anesthesia, caused by the blockade of sympathetic nerve fibers, leading to dilation of blood vessels and capacity vascular bed. As a result, relative hypovolemia occurs, which leads to the development of hypotension. With high epidural blockade, bradycardia may develop as a result of depression sympathetic nerves hearts.

Respiratory system. With high epidural anesthesia, some respiratory depression is possible due to blockade of the intercostal muscles.

Epidural blockade has a bronchodilator effect, which is used in the treatment of status asthmaticus.

Digestive system . As a result of the sympathetic blockade that occurs during epidural anesthesia, intestinal motility increases. This effect is used in the treatment of intestinal paresis. On the other hand, this dictates the need for thorough cleansing of the intestines before a planned operation, because involuntary defecation is possible.

From the outside urinary system Possible urinary retention. True, such complications are quite rare, and are more often caused by the action of narcotic analgesics, especially morphine.

SPINAL ANESTHESIA

A local anesthetic solution is injected with the patient sitting or on his side into the subarachnoid space. Use special thin (No. 24-26) needles. The puncture is usually performed between III and IV lumbar vertebrae. The needle passes through the same anatomical formations as with epidural anesthesia, but in addition it is necessary to puncture the dura mater. Entry into the subarachnoid space is determined by the flow of cerebrospinal fluid from the needle. After this, a local anesthetic solution is injected. Use a 5% solution of lidocaine (1.5 ml) or a 0.25-0.5% solution of bupivacaine (2-3 ml).

The clinical picture and effect on the body of spinal and epidural anesthesia are largely similar. Unlike epidural, the speed of blockade development during spinal anesthesia is higher (no more than 3-5 minutes). Failures and incomplete anesthesia occur less frequently. Spinal anesthesia gives very good muscle relaxation.

During spinal anesthesia, the density of the injected local anesthetic is important. If it is less than the density of the cerebrospinal fluid, the solution is called hypobaric; if it is equal to it, it is isobaric; if it is greater than the density of the cerebrospinal fluid, it is called hyperbaric. Knowing the density of the solution allows you to determine in which direction the local anesthetic will spread. Hypobaric solutions spread upward from the injection site, hyperbaric solutions spread downward, and isobaric solutions remain at the injection level.

INDICATIONS AND CONTRAINDICATIONS FOR EPIDURAL AND SPINAL ANESTHESIA.

Indications for epidural and spinal anesthesia in " pure form"are operations on the lower extremities, pelvic bones, pelvic organs, and anterior abdominal wall.

In combination with multicomponent anesthesia, they can be used for extensive and traumatic operations on top floor abdominal cavity, chest organs.

Epidural and spinal anesthesia are of great importance for the treatment of various pain syndromes in oncology, traumatology, cardiology, etc.

Contraindications are divided into absolute and relative. Absolute symptoms include intolerance to local anesthetics, hypocoagulation, purulent skin diseases at the puncture site, shock, hypovolemia, and hypotension. Relative contraindications are spinal deformities, obesity, and some diseases of the nervous system.

COMPLICATIONS

I. Complications caused by the action of local anesthetic.

These complications can occur with any type of local anesthesia. Three types of complications are most likely to occur: damage to the central nervous system, cardiac conduction system and allergic reactions, as well as their combination. The occurrence and severity of complications depend on the following factors: 1 - the nature of the local anesthetic; 2 - its dose; 3 - type of local anesthesia; 4 - adding vasoconstrictor drugs to the solution.

The stronger the local anesthetic, the more dangerous it is: its strength decreases in the sequence sovcaine - dicaine - trimecaine - lidocaine - novocaine. The most dangerous are spinal, then epidural and regional anesthesia, performed near large vessels (plexus anesthesia).

CNS lesions. The patient becomes restless (less often drowsy), complains of dizziness, ringing in the ears, speech becomes slurred, and metallic taste, nystagmus can often be detected. Convulsive twitching of individual muscles occurs, and in the most severe cases - general convulsions. The latter are especially pronounced in respiratory and metabolic acidosis.

Hemodynamic disorders. The conduction system of the heart and vascular tone (sympathetic blockade) are most affected. Therefore, bradycardia appears (up to cardiac arrest) and blood pressure sharply decreases (up to cardiovascular collapse).

Allergic reactions. There may be allergic dermatitis: the appearance of many red spots on the skin, sometimes on an edematous basis, itching, an attack of bronchial asthma, and in the most severe cases - anaphylactic shock.

Prevention. The main thing is to carefully collect anamnesis. At the slightest suspicion of intolerance to local anesthetics, you should either abandon this method altogether, or use it in preparation antihistamines, benzodiazepines (sibazon, relanium) and phenobarbital. It is very important to use a test dose of local anesthetic (inject it intradermally and evaluate the reaction), not to exceed a single maximum dose and stop anesthesia if there is a suspicion of exposure to large vessel(conduction anesthesia, epidural anesthesia) or into the cerebrospinal fluid tract (epidural anesthesia, paravertebral anesthesia).

Intensive therapy. If the central nervous system is predominantly affected, 2.5-5 mg of sibazone or (carefully!) 2% sodium thiopental solution is administered intravenously until the seizures are eliminated.

If hemodynamic disturbances occur, the patient is transferred to the Trendelenburg position and vigorous infusion therapy is administered. If necessary, vasoconstrictor drugs and glucocorticoid hormones (12 mg dexazone, 60 mg prednisolone) are administered.

In case of cardiac arrest, the entire complex of cardiopulmonary resuscitation is performed.

II. Complications of epidural and spinal anesthesia.

Complications of a traumatic nature. The mildest of them are injuries to the periosteum and spinal ligaments. Manifested by pain at the puncture site. They usually go away on their own within a few days. More serious complications- damage to a vessel with possible formation of an epidural hematoma, damage to a nerve root, puncture of the dura mater. A puncture of the dura mater, if diagnosed in a timely manner, usually does not lead to any serious health problems for the patient, with the exception of headaches that last for several days and are caused by the leakage of cerebrospinal fluid and a decrease in intracranial pressure.

Breathing disorders. This often happens with high epidural and spinal anesthesia, when the roots of the intercostal nerves are blocked. In this case, the only breathing muscle remains the diaphragm. In these conditions, assisted ventilation is sometimes required.

Hemodynamic disorders. As mentioned above, hypotension is an almost constant companion to epidural and spinal anesthesia. A decrease in blood pressure by less than 40% of the initial value is not considered a complication and can be easily stopped by accelerating the infusion rate. When blood pressure decreases by more than 40%, it is necessary to take more vigorous measures: massive infusion therapy, and if it is ineffective, the introduction of vasoconstrictor drugs, preferably ephedrine in a dose of 0.2-0.3 ml.

If the dura mater is punctured unnoticed and a full dose of local anesthetic is administered, a terrible complication can develop - a total spinal block, which is characterized by sharp decline Blood pressure, respiratory arrest. If immediate action is not taken, death may occur. It is necessary to transfer the patient to mechanical ventilation. administration of vasopressors. powerful infusion therapy.

Purulent complications. If the principles of asepsis are not observed, the development of purulent epiduritis and meningitis is possible. Shown powerful antibacterial therapy, and in some cases - surgical intervention to open and drain the purulent focus.

February 7, 1847 can be called a significant day, because it was then that anesthesia was first used. Previously, operations were performed without pain relief, which often led to fatal outcome. Today, two types are widely used: general and local anesthesia. Doctors call the latter procedure anesthesia, but people who are far from medicine prefer the more understandable word “anesthesia.” How does this pain relief method work?

Local anesthesia is an anesthesia that blocks pain in a specific area.

Features of anesthesia (local anesthesia)

The basis of local anesthesia is the blockade of nerve endings in a certain area of ​​the body, that is, anesthesia. The so-called freezing occurs, and pain does not make itself felt. For this purpose, a variety of drugs are used in the form of ointments and injections. For example, one of the most potent anesthetics today is bupivacaine. Its effectiveness can last for 7 hours. “Novocaine”, “trimecaine”, “lidocaine” are also often used in medicine.

The main area of ​​application of local anesthesia is simple surgical interventions that do not require much time. This may include opening ulcers, removing benign tumors, and caesarean section. However, sometimes there may be no talk about surgery. Each of us has encountered local anesthesia during treatment or extraction of teeth, during FGDS.

For special sensitive people Combining anesthetics with sedatives is allowed.

How does local anesthesia differ from general anesthesia?

The choice of anesthesia method is made by the doctor. Many factors are taken into account: individual characteristics, patient's age, presence allergic reactions. If there is even the slightest possibility, then preference is given to operations under local anesthesia. General applies in exceptional cases. For example, when surgery takes a long time. Its peculiarity is the introduction of the patient into an unconscious state, that is, the patient falls into deep sleep.

Which anesthesia is better? Local, of course. This can be confirmed by many arguments:

1. The patient remains conscious and can answer the doctor’s questions.

2. Only small areas are anesthetized, so the effect of anesthetics on the body is less aggressive.

3. No serious consequences. With local anesthesia, if side effects occur, they are minor. For example, an increase in temperature. While general anesthesia can lead to confusion, muscle pain, and vomiting.

There is no need to be afraid of anesthesia. As a rule, today most operations (both with local and general anesthesia) take place with quite predictable results.

Anesthesiology - the science of pain relief and methods of protecting the patient’s body from the extreme effects of surgical trauma.

Pain relief and prevention of undesirable effects of surgical intervention are achieved using local anesthesia (pain relief with preservation of consciousness) or anesthesia (pain relief with temporary shutdown of consciousness and reflexes).

Main stages in the development of anesthesiology

Reached us from Ancient Egypt writings indicate that back in the 3rd-5th millennium BC. Attempts were made to relieve pain during surgical interventions using tinctures of opium, belladonna, mandrake, alcohol, etc. However, the effectiveness of such anesthesia was, of course, scanty, and even the most minor operation often ended in the death of the patient from painful shock.

October 16, 1846 is considered the official birth date of modern anesthesiology. On this day, American dentist William Thomas Morton publicly demonstrated diethyl ether anesthesia when removing a tumor. submandibular region and clearly proved that painless surgical operations are possible. He also had priority in the development of a prototype of a modern anesthesia apparatus - a diethyl ether evaporator. A few months later, ether anesthesia began to be used in England and France, and on February 7, 1847, it was first used in Moscow by F.I. Inozemtsev.

It should be noted that back in 1844, G. Wells (USA) discovered the anesthetic effect of dinitrogen oxide (laughing gas) during tooth extraction. However, the official demonstration of the method to surgeons was unsuccessful, and anesthesia with dinitrogen oxide was long years was discredited, although today combined anesthesia with dinitrogen oxide is used in surgical practice.

Scientists' disputes different countries time has resolved about the discoverers of anesthesia. The founders of anesthesia are considered to be W.T. Morton, his teachers C. Jackson and G. Wells. However, in fairness, to restore truth and priority, a historical fact should be cited, which, unfortunately, was not noted by contemporaries and forgotten by compatriots. In 1844, the newspaper “Russian Invalid” published an article by Ya.A. Chistovich "On amputation of the femur using sulfuric ether." Since all three facts of the first use of anesthesia took place independently of each other and at approximately the same time, W.T. should be considered the discoverer of anesthesia. Morton, G. Wells and Y.A. Chistovich.

The third classic anesthetic drug was discovered by the Englishman James Young Simpson. On November 18, 1847, he published a work on the use of chloroform anesthesia during childbirth. At first, this method became widespread in the medical world and competed quite successfully with the ethereal one. However, the high toxicity of chloroform, the small therapeutic range and, accordingly, frequent complications gradually led to an almost complete abandonment of this type of anesthesia. Despite the invention of a fairly accurate chloroform vaporizer in the 60s, this type of anesthesia has never been rehabilitated. An important reason for this was the synthesis of modern, less toxic anesthetics: cyclopropane, halothane.

The fact that ether anesthesia was carried out in Russia by F.I. was of great importance. Inozemtsev less than 4 months after the demonstration by U.T. Morton and 3 years after the publication of Y.A. Chistovich. An invaluable contribution to the development of anesthesiology was made by N.I. Pirogov. He very soon became an ardent supporter of anesthesia and was one of the first to use anesthesia with diethyl ether and chloroform in Russia, experimentally developed and studied methods of anesthesia, created an apparatus for ether anesthesia (“etherization”), and was the first to point out negative properties anesthesia, possible complications, the need to know the clinical picture of anesthesia, introduced ether and chloroform anesthesia into military field surgery. In the Sevastopol campaign of 1854-1855. under the leadership of N.I. Pirogov performed about 10,000 operations under anesthesia without a single death from it. In 1847 N.I. Pirogov was the first in Russia to use anesthesia during childbirth, then developed methods of rectal, intravascular, intratracheal ether anesthesia, and expressed the idea of ​​superficial “therapeutic” anesthesia.

Ideas N.I. Pirogov served as a prerequisite for the development of intravenous anesthesia. For the first time, intravenous hedonal anesthesia was used by professor of the St. Petersburg Military Medical Academy S.P. Fedorov, who used hedonal, obtained by pharmacologist N.P. Kravkov. Subsequently, this method gained worldwide fame under the name “Russian”. Discovery of N.P. Kravkov and S.P. Fedorov in 1909, intravenous hedonal anesthesia served as the beginning of the development of modern non-inhalation, as well as combined, or mixed, anesthesia.

In parallel with the search for new inhalation anesthetic drugs, the development of non-inhalation types of anesthesia was carried out. In the 30s of the 20th century, derivatives of barbituric acid - hexobarbital and sodium thiopental - were proposed for intravenous anesthesia. These drugs have not lost their importance in anesthesiological practice to this day and are used for intravenous anesthesia. In the 60s of the XX century they were synthesized and introduced into clinical practice sodium oxybate is a substance close to natural metabolites and has a powerful antihypoxic effect, and propanidide is an ultra-short-acting anesthetic drug for intravenous anesthesia.

Along with the development of general anesthesia, methods of local anesthesia were actively developed and improved. V.K. made a great contribution to the development of this section of pain management. Anrep, M. Oberst, G. Brown, A.I. Lukashevich, A. Vir, etc. In 1905, A. Eingorn synthesized procaine, and local anesthesia became widespread. A.V. Vishnevsky developed in detail and introduced into clinical practice methods of infiltration anesthesia with procaine.

Attempts to synthesize an ideal substance for mononarcosis - intravenous or inhalational - were unsuccessful. A more promising option for anesthesia that satisfies the basic requirements of surgeons has become a combination of several drugs that, due to the potentiating effect, can reduce the doses of toxic agents (in particular, diethyl ether, chloroform). However, this type of anesthesia also had a significant drawback, since reaching the surgical stage of anesthesia and muscle relaxation negatively affected the functions of breathing, blood circulation, etc.

A completely new era in anesthesiology began in 1942, when Canadian scientists Griffith and Johnson used the drug curare Intocostrin during anesthesia. Subsequently, short- and long-acting curare-like drugs were synthesized, which became firmly established in anesthesiological practice. Appeared the new kind anesthesia - endotracheal with options for artificial pulmonary ventilation (ALV). This was the impetus for the development of various modifications of artificial respiration devices and, naturally, a qualitatively new direction in thoracic surgery, complex surgical interventions on the abdominal organs, central nervous system (CNS), etc.

The further development of anesthesiology is associated with the development of the principles of multicomponent anesthesia, the essence of which is that, using a combination of drugs for anesthesia and other medications (a combination of narcotic drugs with ganglion blockers, tranquilizers, muscle relaxants, etc.), it is possible to purposefully influence certain structures nervous system.

This principle contributed to the development in the 50s of Labaree and Huguenard of the method of hibernation and neuroplegia using lytic mixtures. However, deep neurovegetative blockade and hibernation are currently not used in anesthesiological practice, since chlorpromazine, which is part of the “cocktail,” suppresses the compensatory reactions of the patient’s body.

The most widespread type of neuroplegia is neuroleptanalgesia (NLA), which allows surgical interventions to be performed with a sufficient degree of pain relief without deep depression of the central nervous system. Anesthesia was maintained with fentanyl, droperidol (intravenously) and endotracheal dinitrogen oxide with oxygen.

The founder of electronic anesthesia is the French scientist Lemon, who for the first time in 1902 conducted experiments on animals. Currently, this type of anesthesia is used in obstetric practice; a special device “Electronesthesia” is used for it, usually in combination with a small amount of analgesic, anticonvulsant and sedatives. The advantages of using this type of anesthesia in obstetrics over others are obvious, since all chemical anesthetics have a depressing effect on the contractility of the uterus and penetrate the placental barrier, affecting the fetus.

Acupuncture anesthesia, as a rule, does not provide complete anesthesia, but significantly reduces sensitivity to pain. It is carried out in combination with analgesics in small doses. This type of anesthesia is performed only by anesthesiologists who have undergone acupuncture training.

During the Great Patriotic War of 1941-1945. the problem of pain relief was successfully resolved with the help of local infiltration anesthesia, as well as ether mask anesthesia.

Surgeons I.S. made a great contribution to the development of domestic anesthesiology in the post-war period. Zhorov, A.N. Bakulev, A.A. Vishnevsky, E.N. Meshalkin, B.V. Petrovsky, A.M. Amosov and others. They actively contributed to the creation of modern anesthesia and respiratory equipment, the development of new methods of anesthesia, and most importantly, they trained numerous students who headed the anesthesiological service in our country.

LOCAL ANESTHESIA

Local anesthesia - reversible elimination of pain sensitivity in a certain part of the body caused by the action of special medications.

Currently, about 50% of surgical operations are performed under local anesthesia.

Indications to local anesthesia are determined by its advantages: no special long-term preoperative preparation; it can be used in cases where there are contraindications to anesthesia; the patient does not need constant postoperative monitoring, as after anesthesia. Operations are performed on an outpatient basis under local anesthesia. Local anesthesia is indicated in cases where performing an operation under intubation anesthesia is associated with a great risk to the patient's life. This group of patients includes elderly and senile people, exhausted, suffering from respiratory and cardiovascular failure. In these cases, anesthesia can be more dangerous than the operation itself.

Contraindications for local anesthesia:

1) patient intolerance to anesthetics due to increased individual sensitivity;

2) age under 10 years;

3) the presence of mental disorders and increased nervous excitability in patients;

4) the presence of inflammatory or scar changes in tissues that prevent the implementation of infiltration anesthesia;

5) ongoing internal bleeding, which requires urgent surgery to stop.

The main drugs for local anesthesia and their properties are given in table. 1.

Table 1. Pharmacological characteristics of local anesthetics.

During general preparation for surgery, the patient is introduced to the features of local anesthesia: consciousness, tactile and deep sensitivity are preserved, but there is no sensation of pain. This psychological preparation. Before the operation, premedication is carried out (injections of solutions of trimeperidine, atropine, droperidol), for patients with labile nervous system tranquilizers are prescribed a few days before the operation.

Methods of local anesthesia, procaine blockades

Infiltration anesthesia according to A.V. Vishnevsky combines the positive qualities of infiltration and conduction anesthesia.

Anatomically, the method is based on the structural features of fascial formations. An anesthetic solution injected under pressure into these cases spreads into them and penetrates the nerves and nerve endings. Tight procaine infiltrates move (creep) along the cases and merge with each other, which is why A.V. Vishnevsky called his method of anesthesia the method of creeping infiltration.

Anesthesia is carried out by the surgeon during the operation, using alternately, as the layer of tissue is dissected, with a syringe and a scalpel.

Tissue infiltration must be carried out before opening the case, since if the case is cut or accidentally damaged, the solution of the anesthetic substance will pour into the wound, as a result of which it will be impossible to create a dense creeping infiltrate, and therefore, to achieve a sufficient analgesic effect. Tight infiltration of tissues with an anesthetic solution carries out hydraulic preparation of tissues; vessels and nerves are easily identified in the infiltrate, which avoids their damage and makes it easier to stop bleeding. For infiltration anesthesia, use 0.25% solutions of procaine or lidocaine with the addition of epinephrine (3 drops of epinephrine solution 1:1000 per 100 ml of anesthetic solution). For case anesthesia it is consumed a large number of solution (up to 800 and even 1000 ml), but due to the low concentration of the anesthetic and the leakage of the solution into the wound when the cases are opened, intoxication occurs during the operation.

An example would be pain relief during surgery. thyroid gland. To administer anesthesia, use 2 syringes (2- and 5-ml or 5- and 10-ml). To numb the skin, an anesthetic solution is injected intradermally with a thin needle, creating a nodule in the form of a “lemon peel” along the entire skin incision line (Fig. 10). Each injection is made at the edge of the nodule formed by the previous injection. Procaine is injected into the subcutaneous tissue through infiltrated skin. Sufficient infiltration of the subcutaneous tissue is determined by raising the entire incision area in the form of a roller.

After dissecting the skin, subcutaneous tissue and subcutaneous muscle of the neck, an anesthetic solution is injected along the midline, infiltrating the muscles, and then under the muscles in the direction up, down and to the sides.

Injecting procaine under the muscles leads to its distribution under the middle layer of the fascia of the neck, while it covers the thyroid gland in the form of a case.

After cutting the neck muscles and dislocating the lobe into the wound thyroid gland additional infiltration of tissue with an anesthetic solution is carried out at the upper and lower poles of the gland and along its posterior surface

Regional anesthesia

Regional anesthesia is performed to numb a specific topographical area or part of the body. There are the following types of regional anesthesia: conduction, intravascular (intravenous, intraarterial), intraosseous, spinal, epidural, etc.

Conduction anesthesia

Its types are divided into the following: anesthesia of nerve trunks, anesthesia nerve plexuses, nerve ganglion anesthesia (paravertebral), spinal and epidural (epidural) anesthesia. The anesthetic is administered peri- or endoneurally.

Conduction anesthesia of the finger according to Lukashevich-Oberst used for operations on the finger (for felons, wounds, tumors). A rubber tourniquet is applied to the base of the finger, distal to which the skin and subcutaneous tissue are anesthetized on the dorsal surface of the main phalanx, and then the needle is advanced to the bone (Fig. 11). After this, the needle is first moved to one side of the bone phalanx and 2-3 ml of a 1-2% solution of procaine or lidocaine is injected, then the other side is anesthetized with the same amount of procaine. Thus, procaine is administered in close proximity to the nerves of the finger that run along its lateral surface.

Intercostal anesthesia used for rib fractures. Having retreated a few centimeters from the site of the rib fracture towards the spine, the skin is anesthetized by intradermal injection of a procaine solution from a syringe with a needle (Fig. 12). A needle is inserted perpendicular to the broken rib at the site of anesthesia of the skin and, as it is advanced until it stops, procaine is slowly injected into the rib. Having pulled the needle 2-3 mm, its end is shifted soft fabrics, advance the needle to the lower edge of the rib, sliding along its surface, and inject perineurally 3-5 ml of a 1-2% solution of procaine, lidocaine. Without removing the needle, return it to the outer surface of the rib, advance it by sliding to its upper edge and inject 2-3 ml of a 1-2% solution of procaine or lidocaine, after which the needle is removed. If several ribs are fractured, the procedure is repeated.

Brachial plexus anesthesia according to Kulenkampf used in operations on upper limb. The patient's position is on his back, his head is turned in the opposite direction, his arm hangs freely from the table. In the middle of the clavicle along its upper edge, the projection of the subclavian artery is determined. The brachial plexus projects outward from the subclavian artery. After infiltrating the skin with a solution of procaine, a long needle without a syringe is inserted outward from the site of pulsation of the artery 1 cm above the collarbone and, sliding along the upper edge of the 1st rib, is moved upward in the direction of the spinous processes of the 1st and 2nd thoracic vertebrae (Th I-II) and reaches the plexus (Fig. 13). The appearance of unpleasant sensations in the hand, a feeling of numbness or a sensation of “shooting” pain indicates a meeting of the needle with one of the nerve trunks of the plexus. The release of blood from the needle indicates that it has entered the vessel. In such cases, the needle is pulled back somewhat and the direction of its travel is changed. After making sure that no blood is released from the needle, 30-35 ml of a 1% solution of procaine or lidocaine is injected. Anesthesia occurs within 10-15 minutes and lasts for 2-6 hours.

Intraabdominal anesthesia of the splanchnic nerves according to Brown used as an addition to local infiltration anesthesia during gastric resection. After laparotomy, the left lobe of the liver is retracted upward and to the right with a hook, and the stomach is retracted to the left and downward. In the area of ​​the lesser omentum, use the index finger of the left hand to feel the pulsation of the aorta above the origin of the celiac artery and rest the finger on the spine to the right of the aorta. Thus, the finger is located between the aorta and the inferior vena cava. For anesthesia, a long needle is used, mounted on a syringe with a 0.5% procaine solution. The needle is passed along the finger of the left hand until it stops at Th XII and then pulled back slightly. By pulling the syringe plunger, make sure that no blood is flowing, and inject 50-70 ml of a 0.5% solution of procaine or lidocaine into the tissue, which spreads into the retroperitoneal space and washes the solar plexus. Anesthesia occurs in 5-10 minutes and lasts 1.5-2 hours.

Procaine blockades

Procaine blockades are the introduction of weak solutions of procaine (0.25-0.5%) or lidocaine into the cellular spaces in order to block the nerve trunks passing through them. Blockades are used for the prevention and treatment of traumatic shock and as a basis for subsequent infiltration anesthesia, as well as for the treatment of certain inflammatory diseases.

Circular (case) blockade of the shoulder perform as follows. On the anterior surface of the middle third of the shoulder when bent in elbow joint Procaine is injected intradermally into the arm with a thin needle to anesthetize the skin. Then, with a long needle attached to a syringe with a 0.25% solution of procaine or lidocaine, the skin, fascia of the shoulder, and biceps brachii muscle are pierced. Preceding the needle stroke with a solution of procaine, pass until humerus; slightly pulling the needle, inject 50-60 ml of a solution to fill the fascial sheath of the biceps muscle with procaine, and at the same level, with the limb straightened, another 50-60 ml of a 0.25% solution of procaine or lidocaine into the sheath of the triceps brachii muscle (Fig. 14).

Circular (case) blockade of the forearm performed in the middle third of the forearm. 60-80 ml of a 0.25% solution of procaine or lidocaine is injected into the fascial sheaths of the flexors and extensors (see Fig. 14).

Circular (case) blockade of the thigh performed by inserting a needle into the middle third of the thigh along the anterior surface, precipitating its movement with a solution of procaine, passing the needle to the bone and, pulling it back slightly, injecting 150-180 ml of a 0.25% solution of lidocaine or procaine (see Fig. 14).

Circular (case) blockade of the leg performed using a similar technique, a solution of procaine is injected into the fascial beds of the flexors and extensors of the leg at the level of its middle third. The needle insertion points are located on the outer and inside tibia. 80-100 ml of a 0.25% solution of lidocaine or procaine is injected into each muscle sheath (see Fig. 14).

Retromammary blockade used to treat initial forms of mastitis or as an element of local anesthesia during operations on the mammary gland (sectoral resection, opening of an abscess). At 3-4 points at the base of the mammary gland (at the upper and lower poles and with outer surface) a 0.5% procaine solution is injected intradermally (Fig. 15).

Then a long needle attached to a syringe, followed by a procaine solution, is injected into the retromammary space. Through each needle insertion, 50 ml of a 0.25% solution of procaine or lidocaine is injected. In this case, no resistance should be felt, and when removing the syringe, procaine should not flow out of the needle. When the blockade is correctly performed, the mammary gland rises and lies as if on a pillow.

Cervical vagosympathetic blockade used for the prevention and treatment of pleuropulmonary shock in chest trauma and as a basis for subsequent anesthesia.

The patient lies on his back with a cushion under his neck, his head is turned in the opposite direction, and the arm on the side of the blockade is pulled down strongly. At the posterior edge of the sternocleidomastoid muscle at a level above or below the intersection of the muscle with the external jugular vein, the skin is anesthetized with a 0.25% procaine solution. By pressing the index finger of the left hand in the place of the nodule formed by procaine, the sternocleidomastoid muscle along with the vessels located under it is moved anteriorly and inward. Using a long needle, placed on a syringe with a 0.25% procaine solution, the skin is pierced through the nodule and, using the procaine solution, the needle is advanced upward and inward, focusing on the anterior surface of the spine. Periodically pull back the syringe plunger to determine possible appearance blood. 40-50 ml of 0.25% procaine solution is administered on each side with a bilateral blockade. A sign of a correctly performed blockade is the appearance after a few minutes of Horner’s sign (dilation of the pupil on the side of the blockade).

Lumbar (perinephric) blockade used for blood transfusion shock, intestinal paresis as a basis for subsequent local anesthesia during operations in the lumbar region and retroperitoneum.

The patient lies on his healthy side, with a cushion under his lower back. The leg located on top is extended, the other is bent at the knee joint. The needle insertion point is located in the corner formed by the XII rib and the long back muscle, departing from the corner along a bisector by 1-1.5 cm. Having anesthetized the skin, a long needle with a syringe is injected perpendicular to the surface of the body and advanced, introducing an anesthetic solution. After passing through the lumbar fascia, which is felt when the end of the needle overcomes an obstacle, the needle enters the perinephric tissue (Fig. 16). By pulling back the syringe plunger, make sure there is no blood and easily inject 60-80 ml of anesthetic on each side. If no drops of solution flow out from the needle disconnected from the syringe, then it is positioned correctly. When blood appears in the needle, tighten it slightly and then inject a solution of procaine. The latter spreads along the retroperitoneal tissue, washing the renal, adrenal, solar plexus and splanchnic nerves.

Intravenous anesthesia

Intravenous anesthesia is used for operations on the extremities (surgical treatment of wounds, reduction of dislocations, reposition of bone fragments, arthrotomy). IN modern conditions This type of pain relief is used extremely rarely. The method is based on the local (due to diffusion into the tissue of the anesthetic drug injected into the vein) effect of the anesthetic substance on nerve endings a limb segment isolated by a tourniquet from the general blood flow (Fig. 17).

By puncture or venesection, the anesthetic is injected into the superficial veins of the forearm or elbow, into the large or small saphenous vein of the leg. To drain venous blood, the limbs are elevated for 1-2 minutes and an elastic bandage or tourniquet is applied proximal to the intended surgical site to stop arterial blood flow. For operations on the foot, lower leg, and knee joint, the tourniquet is applied to the lower third of the thigh; for operations on the hand, forearm, and elbow joint, the tourniquet is applied to the lower third of the shoulder. Instead of elastic bandage You can use a cuff from a device for measuring blood pressure (BP), into which air is pumped until arterial blood flow stops. For operations on the upper extremities, 150-200 ml are used, on the lower extremities - 200-250 ml of a 0.25% procaine solution. At the end of the operation, the tourniquet or cuff is removed slowly to prevent the rapid entry of the procaine solution into the general bloodstream.

Intraosseous anesthesia

Intraosseous anesthesia is a type of intravenous local anesthesia. Rarely used. An anesthetic substance injected intraosseously enters the venous system of the limb, from where it diffuses into the tissue (Fig. 18). Intraosseous anesthesia is used for operations on the limbs. The limb is isolated from the general bloodstream by applying an elastic bandage or a blood pressure cuff. An anesthetic substance is injected on the upper limb into the condyles of the shoulder, olecranon, and bones of the hand, on the lower limb - into the condyles of the femur, ankle, calcaneus. For operations on the upper limb, the tourniquet is applied to the shoulder, for operations on the foot - on the lower third of the leg, for operations on the lower leg - on the lower third of the thigh, and for operations on the thigh - on the upper third.

The skin above the bone puncture site is infiltrated with a 0.25% procaine solution, and then the underlying tissues and periosteum are anesthetized with the same needle. A needle with a needle for bone puncture is passed through the skin, tissue, and with rotational movements it penetrates through the cortical plate into the cancellous bone. For operations on the foot and lower leg, 100-150 ml are used, on the thigh - 150-200 ml, on the upper limb - 100-150 ml of 0.25% procaine solution. After removing the tourniquet, a toxic-resorptive effect of the anesthetic drug (weakness, dizziness, arterial hypotension, nausea, vomiting) may be observed.

To warn toxic effect procaine (which happens if it quickly enters the general bloodstream after the end of the operation), the patient is injected subcutaneously with 2 ml of caffeine solution before removing the tourniquet, then the tourniquet is slowly removed.

Potentiation of effect

The effectiveness of local anesthesia increases when combined with antipsychotic drugs (droperidol) and narcotic analgesics (fentanyl). With combined anesthesia, including local anesthesia and NLA, the effect of local anesthesia increases while the simultaneous beneficial effect of neuroleptics on the psycho-emotional state of the patient.

NLA and central analgesia are used to potentiate the effects of various types of local anesthesia (infiltration, conduction, spinal, epidural), which makes it possible to reduce the dose (and thereby the toxic effect) of both local anesthetics and narcotic substances.

Complications

Complications of local anesthesia are associated with allergic reactions to the administration of an anesthetic drug, an overdose of the latter or epinephrine. Individual increased sensitivity to local anesthetics manifests itself as skin rash, itching, Quincke's edema, laryngo- or bronchospasm. To relieve allergic reactions, antihistamines, glucocorticoids, and antispasmodics are used.

An overdose of an anesthetic substance during local anesthesia occurs when a large amount of the drug enters the bloodstream. Symptoms of overdose are patient anxiety, skin flushing, increased heart rate, increased blood pressure, and convulsions. IN severe cases with increasing intoxication, coma, collapse, respiratory and cardiac arrest develop. Mild manifestations of overdose can be eliminated by introducing barbiturates, narcotic drugs, and inhaling oxygen. In severe cases, cardiac and vasodilators, carry out transfusions of anti-shock blood substitutes, mechanical ventilation, and in case of cardiac arrest - cardiac massage.

Prevention of complications local anesthesia consists of finding out anamnestic data on the tolerability of drugs and compliance with the methodology for its implementation.

Spinal anesthesia

Spinal anesthesia is a conduction anesthesia and is carried out by introducing an anesthetic drug into the subarachnoid space of the spinal cord. Used for operations on organs located below the diaphragm: stomach, intestines, liver and biliary tract, spleen, pelvic organs, and also on the lower extremities. The anesthetic substance blocks the posterior (sensitive) roots of the spinal cord, which leads to loss of pain, tactile, temperature sensitivity, and the anterior (motor) roots with the development of motor paralysis (myorelaxation). Preganglionic sympathetic fibers passing through the anterior roots are also blocked, which causes changes in vascular innervation, leading to dilation of arterioles in the innervation zone. When the sympathetic fibers involved in the formation of celiac fibers are blocked, dilation of the vessels of the abdominal organs, pelvis, and lower extremities can lead to the deposition of blood in them and a drop in blood pressure.

For spinal anesthesia, special needles with a well-fitted mandrel, syringes graduated to tenths of a milliliter, with well-fitted pistons are required. A 2% solution of lidocaine, a 0.5% solution of bupivacaine, a 5% solution of procaine, and a 0.75% solution of bupivacaine in dextrose are used.

The patient is seated across the table, his legs are placed on a stool, his knees should be raised, his back should be bent as much as possible. The nurse stands in front of the patient, bends his shoulders down and helps him maintain his position. When performing a puncture in a lying position, the patient is placed on his side, his back is located on the edge of the table, his knees are pulled to his stomach, his chin is pressed to his chest, his back is bent as much as possible. The assistant stands in front of the patient and, holding the patient by the neck with one hand and the pelvis with the other, fixes him in this position, trying to bend the part of the spine where the puncture is performed.

Rice. 19. Technique of spinal puncture: a - selection of the puncture site with the patient in a sitting position; b — direction of needle advancement depending on the inclination of the spinous process.

The puncture is usually performed between the spinous processes of L III and L IV or L II and L III. The reference point is the spinous process of L IV, which is located on the line connecting the posterior superior iliac spines (Fig. 19). The surgical field is treated with diethyl ether and alcohol. The skin at the injection site is infiltrated with a 0.25% procaine solution. The needle is inserted along the midline between the spinous processes with a slight (5-10°) downward inclination. When the needle passes through the interspinous, supraspinous and yellow ligaments, resistance is felt, which disappears when the ligaments are punctured. Another slight resistance is noted when the dura is punctured; Having overcome it, the needle advance is stopped, the mandrel is removed, the needle is advanced by 2-3 mm with rotational movements, piercing the inner layer of the dura mater. The appearance of clear cerebrospinal fluid indicates a correctly performed puncture. If there is no or insufficient fluid supply, the needle is turned around its axis and moved forward 1-2 mm. If fluid does not appear from the needle or blood is shown, the needle is removed and the puncture is repeated between other spinous processes.

After making sure that the puncture was carried out correctly, 2-3 ml of cerebrospinal fluid is drawn into the syringe, mixed with an anesthetic solution and injected into the spinal canal. The patient is immediately placed on the operating table, lowering the head end of the table by 15? (with the introduction of lidocaine or 0.5% bupivacaine solution) or by lifting it (with the introduction of procaine or 0.75% bupivacaine solution). Giving the patient an appropriate position helps prevent the spread of the anesthetic solution to the upper parts of the spinal cord and medulla oblongata, which depends on the density of the anesthetic substance. Lidocaine solution and 0.5% bupivacaine solution have a lower density than cerebrospinal fluid and therefore will spread upward, while procaine solution and 0.75% bupivacaine solution have a higher density and will spread downward.

Contraindications for spinal anesthesia are traumatic shock, severe intoxication with peritonitis, accompanied by arterial hypotension, inflammatory diseases skin in the back area, spinal deformities.

Heavy complication spinal anesthesia - a decrease in blood pressure caused by blockade of sympathetic fibers. More often, the complication occurs during anesthesia at the level of the lower thoracic and upper lumbar segments of the spinal cord. With anesthesia at the level of the lower lumbar segments of the spinal cord, arterial hypotension usually does not occur. To prevent hypotension, vasoconstrictor drugs are administered before surgery, and if complications occur, they are combined with transfusion of anti-shock blood substitutes. To centralize blood circulation, the lower limbs are raised and bandaged.

When the anesthetic drug spreads up the subarachnoid space, it is possible to turn off the nerve fibers innervating the intercostal muscles, which can lead to respiratory failure or stopping breathing. If respiratory failure occurs, oxygen therapy is used, and if breathing stops, artificial ventilation is used.

IN late period after spinal anesthesia, headache, motor paresis, and purulent meningitis may appear as a consequence of impaired asepsis. Due to complications of spinal anesthesia, its use is limited. Currently, epidural anesthesia is being used more widely.

Epidural anesthesia

Epidural anesthesia is a type of regional anesthesia. The analgesic effect is achieved by blocking the spinal cord roots with an anesthetic drug injected into the epidural space between the dura mater and the periosteum of the vertebrae (Fig. 20). This type of anesthesia has all the positive qualities of spinal anesthesia and is devoid of its disadvantages.

The technique of puncturing the epidural space is similar to that of the subdural space during spinal anesthesia. The puncture can be performed at any level spinal column depending on the nature of the operation. You should remember about the possibility of puncturing the dura mater and getting the anesthetic into the subarachnoid space, which is fraught severe complications. The puncture is performed with a needle placed on a syringe with an isotonic sodium chloride solution. The advancement of the needle is accompanied by resistance when pressure is applied to the piston. As soon as the needle penetrates through the ligaments into the epidural space, resistance when pressing the piston disappears, and the solution is easily injected; the needle is felt to fall. Another sign of a correctly performed puncture is the absence of cerebrospinal fluid leakage from the needle pavilion; when a water pressure gauge is connected to the needle, the pressure detected should be negative. The anesthetic can be injected through a needle or a catheter passed through the needle and left in place for a long time. To prolong anesthesia, drugs can be delivered through the catheter in fractions.

For epidural anesthesia, use a 2% lidocaine solution, a 0.5% bupivacaine solution, and a 0.75% ropivacaine solution. To enhance the analgesic effect during traumatic operations, narcotic analgesics (morphine and fentanyl) are injected into the epidural space. In the postoperative period, long-term epidural blockade is used as effective method pain relief, allowing you to reduce the dose of narcotic analgesics.

Epidural anesthesia is used for traumatological and orthopedic operations on the lower extremities, operations on the abdominal and pelvic organs. This type of pain relief is indicated for elderly and senile people, patients with severe diseases of the cardiovascular and respiratory systems, and metabolic disorders (obesity, diabetes).

Complications rarely occur. Possible arterial hypotension and respiratory disorders, nausea, vomiting, seizures. In 5% of cases, anesthesia does not occur, which is due to the presence of jumpers in the epidural space, limiting the spread of the anesthetic solution.

Anesthesia

Anesthesia- a condition characterized by a temporary shutdown of consciousness, all types of sensitivity (including pain), some reflexes and relaxation skeletal muscles due to the effects of narcotic substances on the central nervous system.

Depending on the route of administration of narcotic substances into the body, inhalation and non-inhalation anesthesia are distinguished.

Theories of anesthesia

Currently, there is no theory of anesthesia that clearly defines the mechanism of the narcotic action of anesthetic substances. Among the existing theories highest value have the following.

Lipid theory proposed by G. Meyer (1899) and C. Overton (1901), who associated the effect of narcotic drugs with their ability to dissolve in fat-like substances of the membranes of nerve cells and thereby disrupt their activity, which leads to a narcotic effect. The narcotic power of anesthetics is directly dependent on their ability to dissolve fats.

According to adsorption theory Traube (1904) and O. Warburg (1914), the narcotic substance accumulates on the surface of cell membranes in the central nervous system, thereby changing the physicochemical properties of cells and disrupting their functions, which causes a state of anesthesia.

In accordance with theory of inhibition of oxidative processes Verworn (1912), the narcotic drug blocks enzymes that regulate redox processes in brain tissue cells.

According to coagulation theory Bernard (1875), Bancroft and Richter (1931), narcotic drugs cause reversible coagulation of the protoplasm of nerve cells, which lose the ability to excite, which leads to the occurrence of narcotic sleep.

The essence physiological theory anesthesia B.C. Galkin (1953), based on the teachings of I.M. Sechenova, I.P. Pavlova, N.E. Vvedensky, comes down to explaining narcotic sleep from the standpoint of inhibition of the central nervous system that occurs under the influence of narcotic substances. Most sensitive to the action of an anesthetic reticular formation brain (Anokhin P.A.).

Thus, the physiological mechanisms of narcotic sleep correspond to modern provisions neurophysiology, and the direct mechanism of action of a drug on a nerve cell is based on one of the chemical or physical processes: effects on cell colloids, cell membranes, lipid dissolution, etc.

Stages of anesthesia

Narcotics cause characteristic changes in all organs and systems. During the period of saturation of the body with a narcotic drug, a certain pattern (stages) is noted in changes in consciousness, breathing, and blood circulation. In this regard, stages are distinguished that characterize the depth of anesthesia. The stages appear especially clearly during ether anesthesia.

There are four stages: I - analgesia, II - excitement, III - surgical stage, divided into 4 levels, IV - awakening.

Analgesia stage (I)

The patient is conscious, but lethargic, dozing, and answers questions in monosyllables. There is no superficial pain sensitivity, but tactile and thermal sensitivity is preserved. During this period, it is possible to perform short-term interventions (opening phlegmons, ulcers, diagnostic studies). The stage is short-term, lasting 3-4 minutes.

Excitation stage (II)

At this stage, inhibition of the centers of the cerebral cortex occurs, but the subcortical centers are in a state of excitement: there is no consciousness, motor and speech excitation is expressed. The patients scream and try to get up from the operating table. The skin is hyperemic, the pulse is frequent, and blood pressure is elevated. The pupils are wide, but react to light, and lacrimation is noted. Often there is a cough, increased bronchial secretion, and vomiting is possible. Surgical manipulations cannot be performed against a background of agitation. During this period, it is necessary to continue saturating the body with a narcotic drug to deepen anesthesia. The duration of the stage depends on the patient’s condition and the experience of the anesthesiologist. Excitation usually lasts 7-15 minutes.

Surgical stage (III)

With the onset of this stage of anesthesia, the patient calms down, breathing becomes even, pulse rate and blood pressure approach the initial level. During this period, surgical interventions are possible. Depending on the depth of anesthesia, there are four level III stages of anesthesia.

First level (III 1). The patient is calm, breathing is even, blood pressure and pulse reach their original values. The pupils begin to narrow, the reaction to light is preserved. Smooth movement of the eyeballs and their eccentric location are noted. The corneal and pharyngolaryngeal reflexes are preserved. Muscle tone is preserved, so carrying out abdominal operations difficult.

Second level (Ш 2). The movement of the eyeballs stops, they are located in a central position. The pupils begin to gradually dilate, their reaction to light weakens. The corneal and pharyngolaryngeal reflexes weaken and disappear by the end of level III 2. Breathing is calm and even. Blood pressure and pulse are normal. A decrease in muscle tone begins, which makes it possible to perform abdominal operations. Usually anesthesia is carried out at level III 1 -III 2.

Third level (Ш 3). Deep anesthesia. The pupils are dilated, react only to a strong light stimulus, and there is no corneal reflex. During this period, complete relaxation of skeletal muscles occurs, including intercostal muscles. Breathing becomes shallow, diaphragmatic. As a result of relaxation of the muscles of the lower jaw, the latter may sag; in such cases, the root of the tongue sinks and closes the entrance to the larynx, which leads to respiratory arrest. To prevent this complication, it is necessary to move the patient’s lower jaw forward and maintain it in this position. The pulse at this level is rapid and of low filling. Blood pressure decreases. You need to know that performing anesthesia at this level is dangerous for the patient’s life.

Fourth level (Ш 4). Maximum dilation of the pupils without their reaction to light, the cornea is dull and dry. Breathing is shallow, carried out due to movements of the diaphragm due to the onset of paralysis of the intercostal muscles. The pulse is threadlike, frequent, blood pressure is low or not detectable at all. Increasing anesthesia to level III 4 is dangerous for the patient’s life, as respiratory and circulatory arrest may occur.

Awakening stage (IV)

As soon as the supply of narcotic substances is stopped, the concentration of the anesthetic in the blood decreases, the patient goes through all stages of anesthesia in reverse order, and awakening occurs.

Preparing the patient for anesthesia

The anesthesiologist is directly involved in preparing the patient for anesthesia and surgery. The patient is examined before the operation, and not only is attention paid to the underlying disease for which the operation is to be performed, but the presence of concomitant pathology is also clarified in detail. If the patient is operated on as planned, then treatment is carried out if necessary concomitant diseases, sanitation of the oral cavity. The doctor finds out and evaluates mental condition the patient, allergy history, clarifies whether the patient has undergone surgery and anesthesia in the past, pays attention to the shape of the face, chest, neck structure, and the severity of subcutaneous fatty tissue. All this is necessary to choose the right method of pain relief and narcotic drug.

An important rule in preparing a patient for anesthesia is cleansing the gastrointestinal tract (gastric lavage, cleansing enemas).

To suppress the psycho-emotional reaction and suppress the functions of the vagus nerve, the patient is given special drug preparation before surgery - premedication. The purpose of premedication is to reduce the incidence of intra- and postoperative complications through the use of medications. A sleeping pill is given at night; patients with a labile nervous system are prescribed tranquilizers (for example, diazepam) 1 day before surgery. 40 minutes before surgery, narcotic analgesics are administered intramuscularly or subcutaneously: 1 ml of 1-2% trimepedine solution or 2 ml of fentanyl. To suppress the functions of the vagus nerve and reduce salivation, 0.5 ml of a 0.1% atropine solution is injected. In patients with aggravated allergy history Premedication includes antihistamines. Immediately before the operation, the oral cavity is examined and removable dentures are removed.

In case of emergency interventions, the stomach is washed out before the operation, premedication is carried out on the operating table, and medications are administered intravenously.

Intravenous anesthesia

The advantages of intravenous general anesthesia are quick induction of anesthesia, lack of agitation, and a pleasant fall asleep for the patient. However, narcotic drugs for intravenous administration create short-term anesthesia, which makes it impossible to use them in their pure form for long-term surgical interventions.

Barbituric acid derivatives- sodium thiopental and hexobarbital cause rapid onset of narcotic sleep. There is no arousal stage, awakening is quick. The clinical picture of anesthesia when using sodium thiopental and hexobarbital is identical. Hexobarbital causes less respiratory depression.

Use freshly prepared solutions of barbiturates. To do this, the contents of the bottle (1 g of the drug) are dissolved in 100 ml of isotonic sodium chloride solution (1% solution) before starting anesthesia. The vein is punctured and the solution is slowly injected at a rate of 1 ml in 10-15 s. After injecting 3-5 ml of solution within 30 seconds, the patient’s sensitivity to barbiturates is determined, then the administration of the drug is continued until the surgical stage of anesthesia. The duration of anesthesia is 10-15 minutes from the onset of narcotic sleep after a single administration of the drug. To increase the duration of anesthesia, fractional administration of 100-200 mg of the drug is used. Its total dose should not exceed 1000 mg. At that time nurse monitors pulse, blood pressure and respiration. To determine the level of anesthesia, the anesthesiologist monitors the condition of the pupils, the movement of the eyeballs, and the presence of the corneal reflex.

Barbiturates, especially sodium thiopental, are characterized by respiratory depression, and therefore, when using it for anesthesia, it is necessary to have breathing apparatus. When apnea occurs, you need to start mechanical ventilation using a breathing apparatus mask. Rapid administration of sodium thiopental can lead to a decrease in blood pressure and depression of cardiac activity. In this case, it is necessary to stop administering the drug. Sodium thiopental is contraindicated in acute liver failure. In surgical practice, barbiturate anesthesia is used for short-term operations lasting 10-20 minutes (opening abscesses, cellulitis, reducing dislocations, repositioning bone fragments). Barbiturates are also used for induction of anesthesia.

Sodium hydroxydione succinate used at a dose of 15 mg/kg, the total dose on average is 1000 mg. The drug is often used in small doses together with dinitrogen oxide. With large doses, arterial hypotension may develop. In order to prevent complications such as phlebitis and thrombophlebitis, the drug is recommended to be administered slowly into the central vein in the form of a 2.5% solution. Sodium hydroxydione succinate is used for induction of anesthesia, as well as for endoscopic examinations.

Sodium hydroxybutyrate administered intravenously very slowly. The average dose is 100-150 mg/kg. The drug creates superficial anesthesia, so it is often used in combination with other narcotic drugs, such as barbiturates. Most often used for induction of anesthesia.

Ketamine can be used for intravenous and intramuscular administration. The estimated dose of the drug is 2-5 mg/kg. Ketamine can be used for mononarcosis and induction of anesthesia. The drug causes shallow sleep, stimulates activity of cardio-vascular system(BP rises, pulse quickens). Ketamine is contraindicated in hypertension. Widely used for shock in patients with arterial hypotension. Side effects of ketamine include unpleasant hallucinations at the end of anesthesia and upon awakening.

Propofol— short-acting intravenous anesthetic agent. Available in ampoules of 20 ml of 1% solution. It is a milky-white, water-isotonic emulsion containing propofol (10 mg in 1 ml) and a solvent (glycerin, purified egg phosphatide, sodium hydroxide, soybean oil and water). Causes a rapid (within 20-30 s) onset of narcotic sleep when administered intravenously at a dose of 2.5-3 mg/kg. The duration of anesthesia after a single injection is 5-7 minutes. Sometimes short-term apnea is observed - up to 20 s, and therefore mechanical ventilation is necessary using an anesthesia machine or an Ambu-type bag. IN in rare cases Allergy and bradycardia may occur. The drug is used for induction of anesthesia, as well as for pain relief for minor surgical operations(opening of phlegmons, abscesses, reduction of dislocations, reposition of bone fragments, laparostomy sanitation of the abdominal cavity, etc.).

Inhalation anesthesia

Inhalation anesthesia is achieved using easily evaporating (volatile) liquids (halothane, isoflurane, etc.) or gaseous drugs (dinitrogen oxide).

Halothane- colorless liquid with a sweetish odor. Boiling point 50.2° C. The drug is highly soluble in fats. Stored in dark bottles, non-explosive. It has a powerful narcotic effect: the introduction of anesthesia is very fast (3-4 minutes), the stage of excitation is absent or weakly expressed, awakening occurs quickly. The transition from one stage of anesthesia to another is rapid, and therefore an overdose of the drug is possible. In its effect on the body, halothane inhibits cardiovascular activity, leads to a slower heartbeat and lower blood pressure. The drug is toxic to the liver, but does not irritate Airways, dilates the bronchi, and therefore can be used in patients with respiratory diseases. It increases the sensitivity of the heart muscle to epinephrine and norepinephrine, so these drugs should not be used during halothane anesthesia.

Diethyl ether, chloroform, and cyclopropane are not used in modern anesthesiology.

Isoflurane- a colorless liquid that does not decompose in light. The same applies to fluoride-containing anesthetics. The surgical level of anesthesia can be maintained with 1-2.5% of the drug in a mixture of oxygen and dinitrogen oxide. Potentiates the effect of all muscle relaxants. During spontaneous ventilation it causes dose-dependent respiratory depression. The use of the drug in an anesthetic concentration leads to a slight decrease in cardiac output, while a slight increase in heart rate is noted. Isoflurane is less likely than other fluorinated anesthetics to sensitize the myocardium to catecholamines. In small concentrations it does not affect blood loss during caesarean section, and therefore it is widely used in obstetrics. When using the drug, even with prolonged anesthesia, there are no cases of toxic effects on the liver and kidneys.

Sevoflurane It was registered in Russia recently, but in the USA, Japan and the European Union it has been used for about 10 years. Anesthesia is more manageable; introductory mask anesthesia is possible, which is convenient in pediatrics and outpatient practice. Toxic reactions when using the drug are not described.

Dinitrogen oxide— “laughing gas”, colorless, odorless, non-explosive, but in combination with diethyl ether and oxygen it supports combustion. The gas is stored in gray metal cylinders, where it is in a liquid state under a pressure of 50 atm. Dinitrogen oxide is an inert gas; it does not interact with any organs or systems in the body and is excreted unchanged by the lungs. For anesthesia, dinitrogen oxide is used only in combination with oxygen; in its pure form it is toxic. The following ratios of dinitrogen oxide and oxygen are used: 1:1; 2:1; 3:1; 4:1. The latter ratio is 80% dinitrogen oxide and 20% oxygen. Reducing the oxygen concentration in the inhaled mixture below 20% is unacceptable, as this leads to severe hypoxia. Under the influence of dinitrogen oxide, the patient quickly and calmly falls asleep, bypassing the stage of excitement. Awakening occurs immediately as soon as the supply of dinitrogen oxide stops. The disadvantage of dinitrogen oxide is its weak narcotic effect; even in the highest concentration (80%) it gives superficial anesthesia. Muscle relaxation absent. Under anesthesia with dinitrogen oxide, small, low-traumatic surgical interventions can be performed.

Muscle relaxants

Muscle relaxants: short-acting (suxamethonium chloride, mivacurium chloride), relaxation time 5-20 minutes, medium-acting (20-35 minutes) - atracurium benzilate, rocuronium bromide; long-acting (40-60 min) - pipecuronium bromide.

Anesthesia devices

For inhalation anesthesia Volatile and gaseous narcotic substances are treated with special devices - anesthesia machines. The main components of the anesthesia machine: 1) cylinders for gaseous substances (oxygen, dinitrogen oxide); 2) dosimeters and evaporators for liquid drugs (for example, halothane); 3) breathing circuit (Fig. 21). Oxygen is stored in cylinders blue color under pressure 150 atm. To reduce the pressure of oxygen and dinitrogen oxide at the outlet of the cylinder, reducers are used that reduce it to 3-4 atm. Vaporizers are designed for liquid narcotic substances and consist of a jar into which the narcotic substance is poured. Vapors of the narcotic substance are directed through the valve into the circuit of the anesthesia machine; the vapor concentration depends on the temperature environment. The dosage, especially of diethyl ether, is carried out imprecisely, in arbitrary units. Currently, evaporators with a temperature compensator are common, which allows you to dose the narcotic substance more accurately - in volume percentages.

Rice. 21. Anesthesia apparatus (diagram): a - cylinders with gaseous substances; b - block of dosimeters and evaporators; c - respiratory system.

Dosimeters are designed for precise dosing of gaseous drugs and oxygen. The most commonly used rotary dosimeters are float-type rotameters. The gas flow inside the glass tube rushes from bottom to top. The displacement of the float determines the minute gas flow rate in liters (l/min).

The breathing circuit consists of a breathing bellows, a bag, hoses, valves, and an adsorber. Through the breathing circuit, the narcotic substance is directed from the dosimeter and evaporator to the patient, and the air exhaled by the patient is sent to the device.

The narcotic respiratory mixture is formed in the anesthesia machine by mixing gases or vapors of narcotic substances with oxygen.

Oxygen, having passed through the dosimeter, is mixed in a special chamber with dinitrogen oxide and cyclopropane, which also passed through the dosimeter, in certain proportions necessary for anesthesia. When using liquid drugs, the mixture is formed when oxygen passes through the evaporator. Then it enters the respiratory system of the device and then into the patient’s respiratory tract. The amount of incoming drug mixture should be 8-10 l/min, of which oxygen should be at least 20%. The ratio of narcotic gases and exhaled air to atmospheric air may be different. Depending on this, there are four methods of circulation (breathing circuits).

1. Open method (circuit). The patient inhales a mixture of atmospheric air that has passed through the evaporator of the anesthesia machine, and exhales into the surrounding atmosphere of the operating room. With this method, there is a large consumption of narcotic substances and their pollution of the operating room air, which is breathed by all medical personnel participating in the operation.
2. Semi-open method (circuit). The patient inhales a mixture of oxygen and a narcotic substance from the apparatus and exhales it into the atmosphere of the operating room. This is the safest breathing circuit for the patient.
3. Semi-closed method (circuit). Inhalation is made from the apparatus, as in the semi-open method, and exhalation is partly into the apparatus, and partly into the atmosphere of the operating room. The mixture exhaled into the device passes through the adsorber, where it is freed from carbon dioxide, enters the respiratory system of the device and, mixing with the resulting narcotic mixture, is again supplied to the patient.
4. The closed method (circuit) involves inhalation and exhalation, respectively, from device to device. The inhaled and exhaled gas mixtures are completely isolated from the environment. The exhaled gas-narcotic mixture, after being released from carbon dioxide in the adsorber, again enters the patient, combining with the newly formed narcotic mixture. This type of anesthesia circuit is economical and environmentally friendly. Its disadvantage is the danger of hypercapnia for the patient if the chemical absorber is not changed in a timely manner or its quality is poor (the absorber must be changed after 40 minutes - 1 hour of operation).

Inhalation anesthesia

Inhalation anesthesia can be performed using mask, endotracheal and endobronchial methods. First of all, you should prepare the anesthesia machine for use. To do this, it is necessary: ​​1) open the valves of the cylinders with oxygen and dinitrogen oxide; 2) check the presence of gas in the cylinders according to the pressure gauge of the gearbox; 3) connect the cylinders to the device using hoses; 4) if anesthesia is carried out with liquid volatile narcotic substances (for example, halothane), pour them into evaporators; 5) fill the adsorber with a chemical absorber; 6) ground the device; 7) check the tightness of the device.

Mask anesthesia

To perform mask anesthesia, the doctor stands at the patient’s head and places a mask on his face. The mask is secured to the head using straps. Fixing the mask with your hand, press it tightly to your face. The patient takes several breaths of air through the mask, then it is attached to the device. Oxygen is allowed to be inhaled for 1-2 minutes, and then the drug supply is turned on. The dose of the drug is increased gradually, slowly. At the same time, oxygen is supplied at a rate of at least 1 l/min. At the same time, the anesthesiologist constantly monitors the patient’s condition and the course of anesthesia, and the nurse monitors blood pressure and pulse levels. The anesthesiologist determines the position of the eyeballs, the condition of the pupils, the presence of a corneal reflex, and the nature of breathing. Upon reaching the surgical stage of anesthesia, they stop increasing the supply of the narcotic substance. For each patient, an individual dose of the narcotic substance in volume percentage required for anesthesia at the first or second level of the surgical stage (III 1 -III 2) is established. If the anesthesia has been deepened to stage III 3, it is necessary to bring the patient’s lower jaw forward.

For this thumbs press on the angle of the lower jaw and move it forward until the lower incisors are in front of the upper ones. In this position, the lower jaw is held with the third, fourth and fifth fingers. You can prevent tongue retraction by using air ducts that hold the root of the tongue. It should be remembered that during anesthesia at stage III 3 there is a danger of drug overdose.

At the end of the operation, the supply of the narcotic substance is turned off, the patient breathes oxygen for several minutes, and then the mask is removed from his face. After finishing work, close all valves of the anesthesia machine and cylinders. The remaining liquid drugs are drained from the evaporators. The hoses and bag of the anesthesia machine are removed and sterilized in an antiseptic solution.

Disadvantages of mask anesthesia

1. Difficult to control.
2. Significant consumption narcotic drugs.
3. Risk of developing aspiration complications.
4. Toxicity due to depth of anesthesia.

Endotracheal anesthesia

With the endotracheal method of anesthesia, the drug enters the body from the device through a tube inserted into the trachea. The advantages of the method are that it ensures free passage of the airways and can be used for operations on the neck, face, and head; the possibility of aspiration of vomit and blood is excluded; the amount of drug used is reduced; gas exchange improves by reducing “dead” space.

Endotracheal anesthesia is indicated for major surgical interventions and is used in the form of multicomponent anesthesia with muscle relaxants (combined anesthesia). The combined use of several drugs in small doses reduces the toxic effects on the body of each of them. Modern combined anesthesia is used to provide analgesia, switching off consciousness, and relaxation. Analgesia and loss of consciousness are achieved by using one or more narcotic substances - inhaled or non-inhaled. Anesthesia is carried out at the first level of the surgical stage. Muscle relaxation (relaxation) is achieved by fractional administration of muscle relaxants. There are three stages of anesthesia.

Stage I - introduction to anesthesia. Introductory anesthesia can be carried out with any narcotic substance that provides sufficiently deep anesthesia sleep without the stage of excitement. Barbiturates are mainly used, and sodium thiopental is also often used. The drugs are administered intravenously in the form of a 1% solution, at a dose of 400-500 mg (but not more than 1000 mg). During induction of anesthesia, muscle relaxants are used and tracheal intubation is performed.

Stage II - maintenance of anesthesia. To maintain general anesthesia, you can use any narcotic that can protect the body from surgical trauma (halothane, dinitrogen oxide with oxygen), as well as NLA. Anesthesia is maintained at the first or second level of the surgical stage (III 1 -III 2), and to eliminate muscle tension, muscle relaxants are administered, which cause myoplegia of all groups of skeletal muscles, including respiratory ones. Therefore, the main condition of the modern combined method of pain relief is mechanical ventilation, which is carried out by rhythmically compressing the bag or fur using an artificial respiration apparatus.

The use of NLA involves the use of dinitrogen oxide with oxygen, fentanyl, droperidol, and muscle relaxants. Intravenous induction anesthesia. Anesthesia is maintained by inhalation of dinitrogen oxide with oxygen in a ratio of 2:1, fractional intravenous administration fentanyl and droperidol - 1-2 ml every 15-20 minutes. If the pulse increases, fentanyl is administered, and if blood pressure increases, droperidol is administered. This type of anesthesia is safer for the patient. Fentanyl enhances pain relief, droperidol suppresses autonomic reactions.

Stage III - recovery from anesthesia. Towards the end of the operation, the anesthesiologist gradually stops administering narcotics and muscle relaxants. The patient regains consciousness, his independent breathing and muscle tone are restored. Adequacy assessment criterion spontaneous breathing- indicators pO 2, pCO 2, pH. After awakening, restoration of spontaneous breathing and skeletal muscle tone, the anesthesiologist can extubate the patient and transfer him for further observation to the recovery room.

Advantages of combined endotracheal anesthesia

1. Quick induction of anesthesia, absence of arousal stage.
2. Ability to operate in the analgesic stage or stage III 1
3. Reducing the consumption of narcotic drugs, reducing the toxicity of anesthesia.
4. Easy controllability of anesthesia.
5. Prevention of aspiration and the possibility of sanitation of the trachea and bronchi.

Methods for monitoring anesthesia

During general anesthesia Constantly determine and evaluate the main parameters of hemodynamics. Blood pressure is measured and pulse rate is determined every 10-15 minutes. In persons with heart and vascular diseases, as well as thoracic operations Constant monitoring of cardiac activity is especially important.

Electroencephalographic observation can be used to determine the level of anesthesia. To monitor pulmonary ventilation and metabolic changes during anesthesia and surgery, it is necessary to conduct a study of the acid-base state (pO 2, pCO 2, pH, BE).

Criteria for the adequacy of anesthesia

1. Absence of tachycardia and stable blood pressure levels.
2. Normal color and natural dryness of the skin.
3. Urine flow - 30-50 ml/hour.
4. Normal level of blood oxygen saturation and CO 2 content.
5. Normal ECG readings.

The deviation of the listed indicators within 20% from the initial level is considered acceptable. During anesthesia, the nurse guides anesthesiology card patient, which necessarily records the main indicators of homeostasis: pulse, blood pressure, central venous pressure (CVP), respiratory rate, mechanical ventilation parameters. This card reflects all stages of anesthesia and surgery, indicates the doses of narcotic substances and muscle relaxants, and notes all drugs used during anesthesia, including transfusion media. The time of all stages of the operation and administration of drugs is recorded. At the end of the operation, the total amount of all drugs used is determined and also recorded in the anesthesia card. A record is made of all complications during anesthesia and surgery. The anesthesia card is included in the medical history.

Complications of anesthesia

Complications during anesthesia may be related to the technique of administering anesthesia or the effect of anesthetic agents on vital organs.

Vomiting, regurgitation

One of the complications is vomit. At the beginning of anesthesia, vomiting may be associated with the nature of the underlying disease (pyloric stenosis, intestinal obstruction) or with the direct effect of the drug on the vomiting center. Dangerous due to vomiting aspiration— entry of gastric contents into the trachea and bronchi. Gastric contents that have a pronounced acidic reaction, reaching the vocal cords and then penetrating the trachea, can lead to laryngospasm or bronchospasm, resulting in respiratory failure followed by hypoxia - the so-called Mendelssohn syndrome, manifested by cyanosis, bronchospasm, tachycardia.

Dangerous regurgitation- passive reflux of gastric contents into the trachea and bronchi. This usually occurs against the background of deep mask anesthesia when the sphincters are relaxed and the stomach is full or after the administration of muscle relaxants (before intubation).

Ingestion of acidic gastric contents into the lungs through vomiting or regurgitation leads to severe pneumonia, often fatal.

To prevent vomiting and regurgitation, it is necessary to remove the contents from the stomach using a probe before anesthesia. In patients with peritonitis and intestinal obstruction the probe is left in the stomach during the entire anesthesia, and a moderate Trendelenburg position is recommended. Before starting anesthesia, to prevent regurgitation, you can use the Selick maneuver - posterior pressure on the cricoid cartilage, which causes compression of the esophagus.

If vomiting occurs, gastric contents should be immediately removed from the mouth using a tampon and suction; in case of regurgitation, gastric contents are removed by suction through a catheter inserted into the trachea and bronchi.

Vomiting followed by aspiration can occur not only during anesthesia, but also when the patient awakens. To prevent aspiration in such cases, it is necessary to place the patient horizontally or in the Trendelenburg position, with the head turned to one side. Monitoring of the patient is necessary.

Breathing complications

Breathing complications may be associated with airway obstruction. This may be due to a malfunction of the anesthesia machine, therefore, before starting anesthesia, it is necessary to check the operation of the device, its tightness and the passage of gases through the breathing hoses.

Airway obstruction may occur as a result of tongue retraction during deep anesthesia (third level of surgical stage of anesthesia - III 3). During anesthesia, solid foreign bodies (teeth, dentures) can enter the upper respiratory tract. To prevent this, it is necessary to advance and support the patient’s lower jaw against the background of deep anesthesia. Before anesthesia, dentures should be removed and the patient's teeth examined.

Complications during tracheal intubation, carried out by direct laryngoscopy, can be grouped as follows: 1) damage to teeth by the laryngoscope blade; 2) damage vocal cords; 3) insertion of an endotracheal tube into the esophagus; 4) insertion of an endotracheal tube into the right bronchus; 5) the endotracheal tube comes out of the trachea or is bent.

The described complications can be prevented with clear knowledge of the intubation technique and control of the position of the endotracheal tube in the trachea above its bifurcation (using lung auscultation).

Complications from the circulatory system

Arterial hypotension - a decrease in blood pressure both during the period of induction of anesthesia and during anesthesia - can occur under the influence of narcotic substances on the heart or vascular-motor center. This happens with an overdose of narcotic substances (usually halothane). Arterial hypotension may appear in patients with low circulating blood volume (BCV) with an optimal dosage of narcotic substances. To prevent this complication, before anesthesia it is necessary to replenish the deficit of blood volume, and during an operation accompanied by blood loss, transfuse blood replacement solutions and blood.

Heart rhythm disturbances(ventricular tachycardia, extrasystole, ventricular fibrillation) can occur due to a number of reasons: 1) hypoxia and hypercapnia resulting from prolonged intubation or insufficient mechanical ventilation during anesthesia; 2) overdose of narcotic substances - barbiturates, halothane; 3) the use of epinephrine against the background of halothane.

To determine the rhythm of cardiac activity, ECG control is necessary.

Treatment depends on the cause of the complication, it includes eliminating hypoxia, reducing the dose of the drug, and using quinine-type drugs.

Heart failure(syncope) - the most serious complication during anesthesia. Its cause is most often an incorrect assessment of the patient’s condition, errors in anesthesia technique, hypoxia, and hypercapnia.

Treatment consists of immediate cardiopulmonary resuscitation.

Complications from the nervous system

During general anesthesia, a moderate decrease in body temperature is often observed due to the effect of narcotic substances on the central mechanisms of thermoregulation, as well as due to cooling of the patient in the operating room.

The body of patients with hypothermia after anesthesia tries to normalize body temperature due to increased metabolism. Against this background, chills occur at the end of anesthesia and after it. Most often, chills occur after halothane anesthesia.

To prevent hypothermia, it is necessary to monitor the temperature in the operating room (21-22 C), cover the patient, if infusion therapy is necessary, transfuse solutions heated to body temperature, inhale warm, moistened narcotics, and monitor the patient’s body temperature.

Cerebral edema— a consequence of prolonged and deep hypoxia during anesthesia. Treatment should begin immediately, observing the principles of dehydration, hyperventilation, and local cooling of the brain.

Damage to peripheral nerves. This complication appears a day or more after anesthesia. The nerves of the upper and lower extremities and the brachial plexus are most often damaged. This occurs when the patient is positioned incorrectly on the operating table (the arm is abducted more than 90° from the body, the arm is placed behind the head, the arm is fixed to the arc of the operating table, the legs are placed on a holder without padding). Correct position the patient on the table eliminates the tension of the nerve trunks.

Treatment is carried out by a neurologist and physiotherapist.